1. Field of the Invention
The present invention relates to a recoil starter of a force accumulation type having rotational force accumulating means such as a spiral spring for accumulating a rotational force of a rope reel which is rotated by pulling a recoil rope, wherein the rotational force accumulated in the accumulating means is transmitted to a crankshaft of an engine to start the engine.
2. Description of the Related Art
A recoil starter of a force accumulation type is known in the art in which a rotational force is accumulated in accumulating means such as a spiral spring by pulling a recoil rope wound around a recoil reel. When the rotational force accumulated in the accumulating means exceeds the load of an engine, the rotational force accumulated in the accumulating means is released and transmitted to a crankshaft of the engine to start the engine. In such a conventional recoil starter of a force accumulation type, when the load of the engine at the engine starting is small, the rotational force accumulated in the accumulating means is released to the engine to rotate the crankshaft before a rotational force sufficient to start the engine has been accumulated. That is, a rotational speed sufficient for starting the engine cannot be obtained and the engine cannot be started with the accumulated rotational force. Therefore, it has been necessary to pull the recoil rope in association with the rotational force accumulated in the accumulating means.
A recoil starter of a force accumulation type has already been proposed in which a rotation of a cam resulting from accumulating means is obstructed until a sufficient rotational force has been accumulated in the accumulating means, wherein in this state, a recoil rope is pulled several times to rotate a rope reel several times so that a sufficient rotational force is accumulated in the accumulating means, and thereafter, the rotational force accumulated in the accumulating means is rapidly released to a crankshaft of the engine by operating an operational lever, so that the engine is started only by the rotational force accumulated in the accumulating means (see, e.g., Japanese Patent Application Laid-Open Publication No. 7-174061).
This conventional recoil starter is constructed so that a rotational force is accumulated in a spiral spring serving as the accumulating means by taking up the spiral spring around an outer peripheral surface of a drum that transmits rotation to the crankshaft of the engine via a centrifugal clutch mechanism. The drum is rotated in a direction opposite to an engine starting direction via a planetary reduction mechanism and a drive shaft rotated by pulling the rope while the drum is engaged with a lock mechanism that obstructs rotation in the engine starting direction, so that the rotational force is accumulated in the spiral spring. Thereafter, the locked state of the lock mechanism is released by operating release means which is separately formed, so that the drum is rapidly rotated by the rotational force accumulated in the spiral spring, whereby the crankshaft is rotated to start the engine.
In this conventional recoil starter, it is necessary to return the recoil rope and further operate the release means after the rotational force has been accumulated in the accumulating means by pulling the recoil rope. In a case where the accumulated rotational force is insufficient and the recoil rope is again pulled, it becomes necessary to again grip a handle of the recoil rope. In addition, since the rotational force remains accumulated in the accumulating means when the recoil starter is left as it stands after pulling the recoil rope, the engine is in danger of starting contrary to one""s intention if one""s hand accidentally touches the release means.
The present invention has been made in order to solve the problems of the above-described conventional recoil starters. Accordingly, it is an object of the present invention to provide a recoil starter which enables a rotational force to be accumulated in accumulating means by pulling a recoil rope with a light pulling force, wherein the rotational force accumulated in the accumulating means is released to an engine to start the engine by fixing a handle for pulling the recoil rope in a main casing.
In order to attain the above object, according to the present invention, there is provided a recoil starter of a force accumulation type. The recoil starter comprises: a main casing provided on an inner side thereof with a reel shaft; a rope reel having a recoil rope wound therearound and rotatably supported around the reel shaft; a recoil spiral spring for rotatingly urging the rope reel in a direction in which the recoil rope is taken up; a cam wheel, rotatably supported around the reel shaft, for transmitting rotation to a rotating member coupled to an engine; accumulating means, disposed between the rope reel and the cam wheel, for accumulating a rotational force due to the rotation of the rope reel, the cam wheel being. rotated by the accumulated rotational force so that the rotating member is rotated via a transmission mechanism; retention means operable to restrain or permit the rotation of the cam wheel; and release means which operates the retention means to restrain the rotation of the cam wheel by pulling a handle attached to an end of the recoil rope, to thereby allow the accumulating means to accumulate a rotational force, and which operates the retention means to permit the rotation of the cam wheel by fixing the handle in the main casing, to thereby allow the rotational force accumulated in the accumulating means to be released to the cam wheel.
In a preferred embodiment of the invention, the retention means comprises a stopper lever engageable with lock pawls formed on the cam wheel to restrain the rotation of the cam wheel, and the release means comprises a release lever that is operated by pulling the handle so that the release lever engages with the stopper lever to restrain the movement of the stopper lever.
In a preferred embodiment of the invention, the release lever includes an operating piece of which an end is disposed to correspond to a support portion for receiving the handle, which support portion is slidably disposed on the main casing, and the release lever is operated via the operating piece due to the handle being received in the support portion and fixed in the main casing, so that the stopper lever is operated to permit the rotation of the cam wheel.
In a preferred embodiment of the invention, the recoil starter further comprises a reduction mechanism in the form of a planetary gear mechanism, interposed between the rope reel and the accumulating means, for transmitting the rotation of the rope reel to the accumulating means at a reduced speed, to thereby reduce the pulling force of the recoil rope.
In a preferred embodiment of the invention, the transmission mechanism comprises a centrifugal ratchet mechanism which includes cam pawls formed on an outer peripheral surface of the cam wheel and centrifugal ratchets that are rotatably disposed on the rotating member disposed at the engine so as to disengageably engage with the cam pawls.